The Journal of Membrane Biology

, Volume 213, Issue 1, pp 39–46

The CLIC1 Chloride Channel Is Regulated by the Cystic Fibrosis Transmembrane Conductance Regulator when Expressed in Xenopus Oocytes

Article

DOI: 10.1007/s00232-006-0059-5

Cite this article as:
Edwards, J.C. J Membrane Biol (2006) 213: 39. doi:10.1007/s00232-006-0059-5

Abstract

CLIC proteins comprise a family of chloride channels whose physiological roles are uncertain. To gain further insight into possible means of CLIC1 channel activity regulation, this protein was expressed in Xenopus oocytes alone or in combination with the cystic fibrosis transmembrane conductance regulator (CFTR). Whole-cell currents were determined using two-electrode voltage-clamp methods. Expression of CLIC1 alone did not increase whole-cell conductance either at rest or in response to increased intracellular cyclic adenosine monophosphate (cAMP). However, expression of CLIC1 with CFTR led to increased cAMP-activated whole-cell currents compared to expression from the same amount of CFTR mRNA alone. IAA-94 is a drug known to inhibit CLIC family channels but not CFTR. In oocytes expressing both CLIC1 and CFTR, a fraction of the cAMP-activated whole-cell current was sensitive to IAA-94, whereas in oocytes expressing CFTR alone, the cAMP-stimulated current was resistant to the drug. Cell fractionation studies revealed that the presence of CFTR conferred cAMP-stimulated redistribution of a fraction of CLIC1 from a soluble to a membrane-associated form. We conclude that when expressed in Xenopus oocytes CFTR confers cAMP regulation to CLIC1 activity in the plasma membrane and that at least part of this regulation is due to recruitment of CLIC1 from the cytoplasm to the membrane.

Keywords

Chloride channelCLICCystic fibrosis transmembrane conductance regulatorcAMP-activated chloride channelCystic fibrosisNCC27CLIC1

Copyright information

© Springer Science+Business Media, Inc. 2007

Authors and Affiliations

  1. 1.UNC Kidney Center and Department of MedicineUniversity of North Carolina at Chapel HillChapel Hill